1. Field of the Invention
This invention relates to a coding apparatus for coding digital signals and a magnetic recording system using the same.
2. Description of the Prior Art
As one of the codes used for coding digital signals, a correlative code is available. The system using this code transmits information of one time slot as a multi-value signal distributed over a plurality of time slots.
Since the information is received as a multi-valued signal, the transmission of information can be effected with a narrower frequency band as compared with systems in which the signal is a binary signal (such as, for example, an NRZ system). In order to transmit information at a narrower frequency band using the correlative code, however, the number of multi-value levels increases unavoidably, so that there exists a problem in that the SN ratio of the transmission line must be improved. In addition, since the above-mentioned correlative code contains a DC component, when the code must be recorded using a magnetic recording system, there arises a problem in that the magnetic recording system is not suited for recording such a code because a magnetic recording system has difficulty in recording DC transmissions.